<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>SharedService test</title>
</head>
<body>
  <button data-op="add">Add</button>
  <button data-op="multiply">Multiply</button>
  <button data-op="slow_subtract">Slow subtract</button>
  <button data-op="throw_error">Throw error</button>
  <div><pre id="output"></pre></div>
  <script src="index.js" type="module"></script>
</body>
</html>